The present invention relates to a prosthetic implant device and more particularly to such implants including porous surfaces thereon. This invention is particularly suitable for use as a femoral component for a hip prosthesis, although is not limited thereto.
Heretofore, various types of porous surfaces have been incorporated into prosthetic implants. Such porous implants are often implanted without the use of any type of bone cement material so that the porous surface will be in direct contact with the bone surface. After a period of time, bony ingrowth occurs in and around the porous surface to biologically affix or further secure the implant in the bone. Alternatively, an implant having a porous surface may be implanted with bone cement, such that the penetration of the bone cement into the porous surface of the prosthesis will enhance the fixation of the prosthesis.
The following U.S. patents disclose prosthetic implants which include various types of porous surfaces:
U.S. Pat. No. 3,906,550 to Rostoker et al. discloses a porous fiber metal structure adapted for attachment to a prosthesis. The fiber metal material is molded directly into the desired precise shape using dies and punches.
U.S. Pat. No. 4,479,271 to Bolesky et al. discloses a prosthesis including porous surfaces which are also either molded and compressed directly into shape or compressed and cut directly into shape.
U.S. Pat. No. 4,536,894 to Galante et al. discloses a prosthesis including porous surfaces in which the porous surfaces are porous pads which are compressed and cut directly to the desired shape and then adhered to substantially flat surfaces.
U.S. Pat. No. 4,570,271 to Sump discloses a prosthesis with a porous surface in which the porous coating is preformed directly into the desired shape which corresponds to the preselected surface of the prosthesis. The preform porous coating is then overlaid onto the preselected surface, compressed, and heated to adhere the preform to the prosthesis. The preform may be produced by conventional multi-layer knitting, braiding, winding, weaving, or other continuous wire processes.
U.S. Pat. No. 4,589,883 to Kenna discloses a prosthesis including a porous surface in which the porous coating is comprised of spherical particles which appear to have been directly bonded to the prosthesis stem.
U.S. Pat. No. 4,636,219 to Pratt et al. discloses a prosthesis including a porous surface comprised of a layered metal mesh structure. The mesh may be bonded to a thin substrate (on the order of 0.010 to 0.012 inch) which thin substrate can then be cut or formed and applied to the body of a prosthesis on a flat surface as in FIG. 3 of Pratt et al. or contoured into specific shapes by processes such as creep forming.
U.S. Pat. No. 4,660,755 to Farling et al. discloses a method for constructing a surgial implant in which a porous layer is bonded to a substrate in the absence of a furnace, the bonding occurring via an electrode.
U.K. Patent Application No. GB2059267A to Ducheyne discloses a type of porous metal wire mesh suitable for use on a prosthesis.
U.K. Patent Application No. GB2142830A to Brown et al. discloses a prosthetic implant having a porous surface provided by a perforated micro-contoured sheet.
U.K. Patent Application No. GB2153233A to Lee et al. discloses a prosthetic implant which utilizes wedges to wedge between the bone cavity wall and the prosthesis stem in which the wedges may include a porous surface.
European Patent Application No. EP0178650A2 to Ducheyne discloses a porous flexible metal fiber material for implantation in conjunction with a prosthesis in which one or more layers of the porous sheet material are pressed against the bone surface with a layer of bone cement then between the implant and the porous sheet material.